VoIP is a technological development in the field of telecommunications that is utilized to transmit voice conversations over a data network using Internet Protocol (IP) packets rather than the existing and traditional telecommunications system more commonly referred to as the Public Switched Telephone Network (PSTN) or Plain Old Telephone Service (POTS). Entities (e.g., businesses or individuals) implement VoIP by purchasing and installing the necessary equipment (e.g., one or more Customer Premise Equipment (CPE) devices) to access a VoIP service provider and activating this telecommunication service via a broadband Internet connection.
Typically, entities will not have solely telecommunications equipment connected to the broadband Internet connection. Various other data networking devices including but not limited to computers, peripherals and wireless networking devices will comprise a substantial Local Area Network (LAN) that is connected to a Wide Area Network (WAN) with a multitude of services available via the broadband Internet connection. With the growing amount video and rich content (iTunes, You-Tube etc.) being available on the Internet, entities are increasingly downloading large files, which has the potential to saturate a broadband Internet connection in the downstream direction (i.e., towards the LAN). P2P applications like Bit-Torrent are also starting to inundate broadband Internet connections in both directions. Some VoIP equipment have upstream Quality of Service (QoS) capabilities which prioritize voice-type traffic ahead of other application traffic, thereby ensuring high voice quality towards the remote party (towards the WAN). However, QoS capabilities are limited in the downstream direction, which causes VoIP customers to experience poor voice quality when someone on their LAN (i.e., a home network) starts a large download.
FIG. 1 is a system level diagram depicting a prior art data network 100 that also functions, in part, as a telecommunication system based on VoIP. The data network 100 includes various components such as cable modem termination system (CMTS), a DSLAM or other edge router/switch such as a Metro Ethernet router 112 used to provide high speed data services via an integrated data network 114 (e.g., the Internet) between various devices. Such devices include servers 116, customer networks 105 connected via a cable modem 102 and POTS devices 124 connected by the PSTN 122, telephony gateway(s) 120 and media relay(s) 118. A customer network 105 may be further defined by a VoIP telephony adapter 104 that connects to one or more telephony devices 106 and also functions as a router to create Ethernet based connections 108 to other customer equipment such as a laptop computer 110 (via wired or wireless protocols known to those skilled in the art). For the purposes of this discussion, connections and components behind the VoIP telephony adapter 104 define a LAN 101 while connection and components in front of the VoIP telephony adapter 104 define a WAN 103.
The downstream bandwidth between the server 116 and a CMTS 112 is typically higher than that of the customer's broadband link. Therefore, when the customer starts a download 123, typically with a Transmission Control Protocol/Internet Protocol (TCP/IP)-based protocol, TCP rate control quickly ratchets up the downstream bandwidth utilization to the level of the lowest bandwidth link in the chain, which is usually the customer's broadband link. If, during this download, a voice communication session 121 occurs, there is packet queuing (delay & jitter) and packet drops 113 at the CMTS 112 in the downstream direction, both of which contribute to poor voice quality. The upstream bandwidth is usually not severely affected, since TCP ACK packets in the upstream direction are of very small size (typically less than 50 bytes), and fewer in number than downstream TCP packets.
Accordingly, there is a need in the art for an apparatus and method for providing voice traffic management in a data network to improve the overall experience of VoIP telephony.